1. Field of the Invention
The present invention relates to a printed circuit board (PCB), and more particularly, to a PCB, a backlight unit having the PCB and a liquid crystal display (LCD) device having the PCB.
2. Description of the Related Art
A liquid crystal display (LCD) device displays images by using liquid crystal, of which electrical and optical characteristics vary in response to an electric field applied thereto. LCD devices have various characteristics such as being thin, having a lower driving voltage, having a lower power consumption, etc., than other types of display devices such as cathode ray tube (CRT) devices, plasma display panel (PDP) devices, etc. Therefore, LCD devices are used in notebook computers, monitors, televisions, mobile phones, etc. An LCD device is a non-emissive type display device, and thus the LCD device necessarily requires a light source, such as a backlight assembly to supply an LCD panel of the LCD device with light.
A conventional LCD device mainly employs a light source, such as a cold cathode fluorescent lamp (CCFL), a flat fluorescent lamp (FFL), a light-emitting diode (LED), etc., which emits white light. LEDs may be manufactured in a chip form and have low power consumption, good color reproduction, high luminance and so on. Accordingly, LEDs are being used for light sources of backlight assemblies.
However, LEDs have a disadvantage in that LEDs emit a large amount of heat. The heat generated from an LED may deteriorate an LED chip and a fluorescent substance used thereon, and affect other characteristics of the LED chip. Moreover, the heat generated from the LED may increase the inner temperature of an LCD device that uses the LED as a light source, so that liquid crystal molecules of the LCD device may be deteriorated or an optical member of the LCD device may become wrinkled such that the display quality of the LCD device may be decreased. In particular, the heat emitted from the LED may be a particular concern when a high-luminance LED is used in the LCD device.